Forecasting the 2019 hurricane season: A look back and ahead
Analyzing 2018's hurricane season predictions and actual activity can help us in preparing for the 2019 season ahead.
The Atlantic hurricane season begins on June 1 and ends November 30. The Atlantic basin had three quiet seasons from 2013 to 2015, followed by slightly higher activity in 2016 and an extremely active season in 2017.
The 2018 Atlantic hurricane season was slightly above average and will primarily be known for two storms that brought significant damage and loss of life to the U.S.
Hurricane Florence made landfall as a Cat 1 hurricane in southeastern North Carolina on September 14, but, like Harvey in 2017, it slowed down considerably, bringing record flooding to portions of the region where it dumped up to 36 inches of rain — the equivalent of nine trillion gallons of water causing at least 55 deaths with economic losses reaching $17.9bn.
On October 7, Hurricane Michael formed and strengthened over the Gulf of Mexico, making landfall as a Cat 5 hurricane in the Florida Panhandle with wind speeds up to 155 mph and storm surge up to 14 feet. Damages in the US are estimated to have exceeded $15bn.
Accuracy of pre-season forecasts in 2018
Pre- and early-season forecasts predict a near to slightly above average Atlantic Hurricane season. While 2018 was to be an El Niño year (one in which warming of surface waters in the eastern tropical Pacific Ocean occurs) the water temperatures remained closer to normal than expected, with only a slight trend towards warming.
Therefore, later seasonal forecasts underestimated Atlantic hurricane activity. These downward adjustments were primarily due to anomalous tropical Atlantic sea surface temperature (SST) cooling. Despite a relatively cold tropical Atlantic, early September 2018 was extremely active and was the primary driver of the slightly above average season that occurred.
A look ahead at the 2019 hurricane season
One of the driving factors for Atlantic hurricane development is the condition of the global climate and whether it will be influenced by El Niño, La Niña or a neutral phase. Generally, El Niño tends to decrease hurricane activity in the Atlantic Ocean.
The current El Niño phase is likely to persist and potentially even strengthen over the summer and fall. However, if the El Niño weakens and goes neutral, the number of tropical storms and hurricanes could be above normal.
Outlook: Above-average hurricane season
The table below summarizes the predicted number of storm events for 2019 by several meteorological organizations. Regarding the predicted numbers of tropical storm events, taking all predictions together, the 2019 hurricane season is expected to be near normal with 12 to 16 tropical storms forecasted. (An average season usually has five to seven storms reaching hurricane strength and two to four becoming major hurricanes).
The predicted number for storms and hurricanes making landfall in the US by Tropical Storm Risk (TSR) is below the long-term norm with one hurricane landfall. However, those predictions are associated with even higher uncertainties, which is why most institutes refrain from issuing hurricane landfall projections.
It should be stressed that the precision of hurricane outlooks issued in April and May is low, and thus forecast uncertainties remain large for the 2019 hurricane season. These uncertainties apply already to the underlying projections for the El Niño Southern Oscillation and the North Atlantic Oscillation.
Preparing for what lies ahead
At present, the established research institutes have predicted near normal activity for the 2019 Atlantic basin hurricane season. While scientists from Colorado State University (CSU) and TSR anticipate slightly below normal activity, North Carolina State University (NCSU) and AccuWeather predict slightly above normal activity and Global Weather Oscillation (GWO) and the National Oceanic and Atmospheric Administration (NOAA) a near-normal hurricane season.
It is important to consider that only one hurricane or a superstorm like Sandy making landfall could have a catastrophic impact on the insurance industry. It does not require an active hurricane season for the insurance market to experience significant losses.
We may not know for certain what the future holds, and therefore, it is extremely important that any business located in a hurricane-prone area be prepared to mitigate against the risk of wind, water and storm surge and have an adequate continuity plan rehearsed and in place just in case — not only this season, but each and every year.
Andrew Higgins is the senior regional technical & expertise manager at Allianz Global Corporate & Specialty. He can be reached at andrew.higgins@agcs.allianz.com.
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